Fastener driving devices typically have trigger assemblies that operate in either a “sequential” mode (“place and actuate” mode) or a “contact” mode. In sequential actuation trigger assemblies, the nose of the device must be forced against the workpiece before the trigger is enabled. Therefore, the operator cannot simply pull the trigger to fire the device. Rather, the device must be forced downwardly against the workpiece so that a contact trip assembly associated with the nose moves upwardly to engage an actuator that will render the trigger operative, so that the subsequent pulling of the trigger will fire the device. If the tool recoils, no actuation of the device will occur until the trigger is released and the proper sequence of movement is followed.
In contact actuation trigger assemblies, the trigger is pulled before the nose of the device makes contact with the workpiece. This places the actuator in a position such that the device may be actuated every time the nose of the device is forced against the workpiece. With this sequence of activation, the operator can hold the trigger and subsequently force the nose against the workpiece to fire the device.
Each of the sequential and contact actuation trigger assemblies have advantages depending on the specific application. For example, sequential actuation trigger assemblies eliminate the possibility of accidental double actuation of the device. This is particularly advantageous when using the device for placing joist hangers, for example.
One aspect of the present invention is to provide a fastener driving device having a trigger assembly capable of being automatically switched between a sequential mode and a contact mode.
In accordance with the principles of the present invention, this aspect may be achieved by providing a fastener driving device including: a portable frame constructed and arranged to be manually handled, the frame defining a fastener driving track; a magazine assembly constructed and arranged to feed successive fasteners from a supply of fasteners along a feed track into the drive track; a fastener driving element mounted in the drive track; a power system constructed and arranged to move the fastener driving element through successive operating cycles each of which includes a drive stroke operable to drive a leading fastener fed along the feed track into the drive track outwardly into a workpiece and a return stroke; an actuating assembly constructed and arranged to actuate the power system to move through an operating cycle, including an input actuator movable from an inoperative position into an operative position to actuate the power system; a contact trip assembly mounted for movement from an inoperative position into an operative position in response to the engagement of the tool with a workpiece; and a trigger assembly operatively disposed between the contact trip assembly and the actuating assembly. The trigger assembly includes: a trigger member pivoted to the frame for movement between inoperative and operative positions; and an actuating member having a connection with the trigger member and a free end cooperable with an output actuator of the contact trip assembly constructed and arranged to enable a portion of the actuating member to move the input actuator of the actuating assembly into its operative position in response to movement of the contact trip assembly and the trigger member into the operative positions thereof. The connection of the actuating member with respect to the trigger member is constructed and arranged to accommodate movement of the actuating member with respect to the trigger member between (1) a first position wherein the free end of the actuating member can be moved into a position in which the free end is retained in the path of movement of the output actuator following rebound or manual movement of the contact trip assembly out of its operative position while the trigger member is retained in its operative position following an actuating movement of the input actuator, and (2) a second position wherein the free end of the actuating member can be moved into a bypass position in which the free end is out of the path of movement of the output actuator following the rebound or manual movement of the contact trip assembly out of its operative position while the trigger member is retained in its operative position following an actuating movement of the input actuator. The trigger assembly also includes an automatic mode selecting mechanism including a mode selecting member having a connection with the actuating member constructed and arranged to make the mode selecting member (1) to move with the actuating member with respect to the trigger member between the first and second positions of the actuating member, and (2) to have a relative movement with respect to the actuating member so that the mode selecting mechanism (a) retains the actuating member in the first position thereof in response to an initial movement of the trigger member to the operative position thereof, and (b) retains the actuating member in the second position thereof in response to an initial movement of the contact trip assembly into the operative position thereof and a subsequent movement of the trigger member into the operative position thereof.
Another aspect of the present invention is to provide a trigger assembly for a fastener driving device including: a portable frame constructed and arranged to be manually handled, the frame defining a fastener driving track; a magazine assembly constructed and arranged to feed successive fasteners from a supply of fasteners along a feed track into the drive track; a fastener driving element mounted in the drive track; a power system constructed and arranged to move the fastener driving element through successive operating cycles each of which includes a drive stroke operable to drive a leading fastener fed along the feed track into the drive track outwardly into a workpiece and a return stroke; an actuating assembly constructed and arranged to actuate the power system to move through an operating cycle, including an input actuator movable from an inoperative position into an operative position to actuate the power system; and a contact trip assembly mounted for movement from an inoperative position into an operative position in response to the engagement of the tool with a workpiece. The trigger assembly includes: a trigger member pivoted to the frame between the contact trip assembly and the actuating assembly for movement between inoperative and operation positions; and an actuating member having a connection with the trigger member and a free end cooperable with an output actuator of the contact trip assembly constructed and arranged to enable a portion of the actuating member to move the input actuator of the actuating assembly into its operative position in response to movement of the contact trip assembly and the trigger member into the operative positions thereof. The connection of the actuating member with respect to the trigger member is constructed and arranged to accommodate movement of the actuating member with respect to the trigger member between (1) a first position wherein the free end of the actuating member can be moved into a position in which the free end is retained in the path of movement of the output actuator following rebound or manual movement of the contact trip assembly out of its operative position while the trigger member is retained in its operative position following an actuating movement of the input actuator, and (2) a second position wherein the free end of the actuating member can be moved into a bypass position in which the free end is out of the path of movement of the output actuator following the rebound or manual movement of the contact trip assembly out of its operative position while the trigger member is retained in its operative position following an actuating movement of the input actuator. The trigger assembly also includes an automatic mode selecting mechanism including a mode selecting member having a connection with the actuating member constructed and arranged to make the mode selecting member (1) to move with the actuating member with respect to the trigger member between the first and second positions of the actuating member, and (2) to have a relative movement with respect to the actuating member so that the mode selecting mechanism (a) retains the actuating member in the first position thereof in response to an initial movement of the trigger member to the operative position thereof, and (b) retains the actuating member in the second position thereof in response to an initial movement of the contact trip assembly into the operative position thereof and a subsequent movement of the trigger member into the operative position thereof.
These and other aspects, features and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, the principles of this invention.